isalnum function in C

The C library function isalnum return non zero if character is alphanumeric (a-z, A-Z, 0-9) otherwise, it shall return 0.
Header File - #include<ctype.h>
Syntex - isalnum(variable name)

Isalnum() alphanumeric Example

#include<stdio.h> #include<conio.h> #include<ctype.h> void main() {        char numchar='A';        if(isalnum(numchar))        {         printf("numchar = %c alphanumeric \n ",numchar);        }        else        {         printf("numchar = %c is not alphanumeric \n ",numchar);            }        getch(); }                          Output

Isalnum() non alphanumeric Example

#include<stdio.h> #include<conio.h> #include<ctype.h> void main() {        char numchar='$';        if(isalnum(numchar))        {         printf("numchar = %c alphanumeric \n ",numchar);        }        else        {         printf("numchar = %c is not alphanumeric \n ",numchar);            }        getch(); }                          Output